The pushback will be TEACHERS UNIONS. Keep them in high school longer means more teachers/more dues/more power. I know one girl who dropped out of high school because she had one English credit left and her school demanded she fill up the rest of the day with electives. Why? She dropped out and took the GED. The problem is the “stigma” of the GED... there is one. That will have to change and be looked upon as an “educational choice”. IMHO
We need to have stigmas attached to students loans... and I can imagine ‘I got my GED at 16 so I could ______ instead waste time in school.’ is a statement that would be respected by the vast majority of people not heavily invested in academia.
They will start adding other requirements to get a High School Degree, like “volunteering” for certain activities.